The present invention relates generally to engines or power devices and, more particularly, to internal combustion engines.
Many known conventional internal combustion engines typically have a camshaft for controlling the operation of engine valves such as air intake and exhaust valves. One disadvantage of this arrangement is the inherent parasitic power losses associated with camshafts as well as the relatively slow mechanical actuation of such engine valves which is fixed to engine speed. Another disadvantage is that the timing for opening and closing such engine valves is typically fixed to crankshaft and piston position and generally can be optimized for only one operating condition. Consequently, performance and emissions of the engine may be less than optimum at many other operating conditions. Other known internal combustion engines, described in technical literature, eliminate the camshaft and instead hydraulically actuate such engine valves. However, the electrical actuators used to control such engine valves are typically solenoids which still act too slow and continuously consume electrical power throughout the time such engine valves are opened. It is therefore desirable to provide higher speed of actuation, greater flexibility, and conservation of energy in the operation of such engine valves.
Some known engines have exhaust-driven turbochargers for improving the power output and efficiency of an engine. However, such turbochargers typically require complex high precision parts and are slow to respond to increased loads on the engine.
Known engines typically may shut down completely when a failure occurs. Such engine failure and shutdown may quickly lead to more catastrophic damage and/or injury if the engine is, for example, powering a moving occupied vehicle or other craft.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention, there is disclosed a power module comprising an air compressor chamber, an air supply valve operable to control air flow to the air compressor chamber, a movable air pump piston positioned in the air compressor chamber, a combustion chamber separate from the air compressor chamber, an air storage chamber arranged in fluid communication between the air compressor chamber and the combustion chamber, an intake valve operable to control air flow from the air storage chamber to the combustion chamber, an exhaust valve operable to control exhaust gas flow from the combustion chamber, and a movable power piston positioned in the combustion chamber.
In another aspect of the present invention, there is disclosed a power module comprising a turbocharger, an air compressor chamber, a free air supply valve operable to control ambient air flow to the air compressor chamber, a turbocharged air supply valve operable to control the flow of turbocharged air from the turbocharger to the air compressor chamber, a movable air pump piston positioned in the air compressor chamber, a combustion chamber separate from the air compressor chamber, an air storage chamber arranged in fluid communication between the air compressor chamber and the combustion chamber, an intake valve operable to control air flow from the air storage chamber to the combustion chamber, a free exhaust valve operable to control exhaust gas flow from the combustion chamber to ambient, a drive exhaust valve operable to control exhaust gas flow from the combustion chamber to the turbocharger, and a movable power piston positioned in the combustion chamber.
In another aspect of the present invention, there is disclosed a power module comprising an actuating fluid compressor chamber, an actuating fluid supply valve operable to control actuating fluid flow to the actuating fluid compressor chamber, a movable actuating fluid pump piston positioned in the actuating fluid compressor chamber, an actuating fluid common rail, a combustion chamber separate from the actuating fluid compressor chamber, an actuating fluid storage chamber arranged in fluid communication between the actuating fluid compressor chamber and the actuating fluid common rail, a hydraulically-actuatable intake valve operable to control air flow to the combustion chamber, a hydraulically-actuatable exhaust valve operable to control exhaust gas flow from the combustion chamber, and a movable power piston positioned in the combustion chamber.
In another aspect of the present invention, there is disclosed a power module comprising an air compressor chamber, an air supply valve operable to control air flow to the air compressor chamber, a movable air pump piston positioned in the air compressor chamber, an actuating fluid common rail, a combustion chamber separate from the air compressor chamber, an air storage chamber arranged in fluid communication between the air compressor chamber and the combustion chamber, an actuating fluid compressor chamber, an actuating fluid supply valve operable to control actuating fluid flow to the actuating fluid compressor chamber, a movable actuating fluid pump piston positioned in the actuating fluid compressor chamber, an actuating fluid storage chamber arranged in fluid communication between the actuating fluid compressor chamber and the actuating fluid common rail, a hydraulically-actuatable intake valve operable to control air flow to the combustion chamber, a hydraulically-actuatable exhaust valve operable to control exhaust gas flow from the combustion chamber, and a movable power piston positioned in the combustion chamber.
In another aspect of the present invention, there is disclosed an internal combustion engine comprising a plurality of power modules wherein each power module includes an air compressor chamber and an air storage chamber. The air compressor chamber and air storage chamber of each power module are isolated from fluid communication and independently operable with respect to the air compressor chamber and air storage chamber of any other power module of the internal combustion engine.
In another aspect of the present invention, there is disclosed an internal combustion engine comprising a plurality of power modules wherein each power module includes an actuating fluid compressor chamber and an actuating fluid storage chamber. The actuating fluid compressor chamber and actuating fluid storage chamber of each power module are isolated from fluid communication and independently operable with respect to the actuating fluid compressor chamber and actuating fluid storage chamber of any other power module of the internal combustion engine.
In another aspect of the present invention, there is disclosed a power module including a rotatable crankshaft, combustion chamber, a movable power piston positioned in the combustion chamber, a fuel injector operable to inject fuel into the combustion chamber, a hydraulically-actuatable intake valve operable to control air flow into the combustion chamber, and a hydraulically-actuatable exhaust valve operable to control exhaust gas flow from the combustion chamber. The crankshaft is selectively rotatable in one of a first angular direction and a reverse angular direction in response to selectable operation of the intake and exhaust valves and fuel injector relative to the position of the power piston.
In another aspect of the present invention, a method of operating a power module is disclosed comprising the steps of moving a power piston from its expansion position and towards its contraction position, closing an exhaust valve, and then closing an intake valve before the power piston reaches its contraction position.
One embodiment of the subject invention provides one or more power modules that are capable of operating as a dynamically-variable (e.g., 2, 4, 6, 8, etc.) stroke cycle engine. Each power module when switched to a two-stroke engine cycle is particularly advantageous for developing more power (i.e., more work per unit time or stroke) in a relatively smaller package (e.g., fewer combustion cylinders and related components) compared to conventional two-stroke or four-stroke internal combustion engines. The selectable greater number of strokes per engine cycle of one embodiment of the subject invention are particularly advantageous for facilitating longer duration of containment of exhaust gas within the combustion chamber to ensure more complete burning of combustion byproducts.
The combustion chamber of each power module is capable of developing relatively high peak fluid pressures that result in relatively higher power output capability. During operation ol the power module, the combustion chamber preferably maintains a residual or minimum fluid pressure greater than atmospheric pressure even when the power piston is at its expansion position. Such residual fluid pressure enables relatively high peak fluid pressures on subsequent engine cycles and thus greater engine efficiency. Each power module has a compressor cell for locally compressing and pumping air and actuating fluid and a separate combustion cell for the generation of power. By dividing these functions into separate cells, each cell advantageously has a larger surface area available for handling the passage of required fluids.
One embodiment of the subject power module also substitutes digitally-controlled hydraulic valve actuators for conventional camshafts. This improved arrangement provides conservation of electrical energy and greater flexibility for independent control of air, fuel, and exhaust during an engine cycle. The actuators can be dynamically controlled to selectively reverse the rotating direction of the engine crankshaft that simplifies the transmission coupled to the engine. They may also provide engine compression braking and energy recovery when deceleration is desired and/or vary the number of strokes per engine cycle. The above modular design also provide greater safety in terms of relatively low external fluid pressures, relatively low electrical voltages, and limp-home capability in the event of a localized failure. The ability of one embodiment of the subject power module or engine to dynamically vary the number of strokes per engine cycle may enable the power module to exhibit lower noxious emissions than conventional engines.